The goal of this program is to advance the understanding of pathology underlying the Sudden Infant Death Syndrome, with particular reference to sleep and sleep-related disorders. We will perform 24-hour polygraphic monitorings on infants who have had a "near miss" Sudden Infant Death episode, on siblings of SIDS victims, on "low-risk" (control) infants and premature infants during which respiratory and cardiac variables will be continuously recorded. These variables will then be analyzed with references to sleep and wakefulness, and to the various sleep stages. In addition, we will also study chemo reflexes during sleep and wakefulness. At this time, specific evaluations of the neurological states of the infants, using the Amiel-Tison scale, will be made. For each infant recorded, a longitudinal data survey will be made. During the first year of life, each infant will be recorded at specific times. Some infants will be followed for up to 3 years, if such follow-up is indicated by the results of the recordings and under specific protocols. Finally, we propose to perform recordings on children of sleep apnea patients to determine whether a significant population "at risk" exists.